R-T-B based permanent magnet

Patent metadata

Field	Value
Publication number	US-10068691-B2
Application number	US-201514661722-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Mar 28, 2014
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

An R-T-B based permanent containing main phase grains with a composition of (R1-xYx)2T14B (R is rare earth element(s) composed of one or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, T is one or more transition metal elements including Fe or a combination of Fe and Co as essential elements, and 0.2≤x≤0.7), wherein the residual magnetic flux density Br is 1.1 T or more, the coercivity HcJ is 400 kA/m or less, and the ratio Hex/HcJ of the external magnetic field Hex required for obtaining a residual magnetic flux density Br of 0 to the coercivity HcJ is 1.10 or less.

First claim

What is claimed is:

1. An R-T-B based permanent magnet comprising main phase grains with a composition of (R 1-x Y x ) 2 T 14 B with a residual magnetic flux density Br of 1.1 T or more and a coercivity HcJ of 400 kA/m or less, wherein:
a ratio (Hex/HcJ) of the external magnetic field of Hex to the coercivity (HcJ) is 1.10 or less, where:
the Hex is the external magnetic field required for obtaining a residual magnetic flux density Br of 0,
R is rare earth element(s) composed of one or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu;
T is one or more transition metal elements including Fe or a combination of Fe and Co; and
0.2≤x≤0.7.

2. A rotating machine comprising the R-T-B based permanent magnet of claim 1 .

Assignees

• Tdk Corp

Inventors

• Suzuki Kenichi

Classifications

• H01F1/0571 Primary

  in the form of particles, e.g. rapid quenched powders or ribbon flakes · CPC title

• H01F1/0577 Primary

  sintered · CPC title